Julius Sumner Miller, a heralded physicist known on television as "Professor Wonderful" to millions of children on the 1950s "Mickey Mouse Club," as a strict taskmaster to students in his classroom and most recently as a critic of what he saw as America's intellectual decline, has died at his Torrance home.

He was 78 and told a reporter in his last interview two weeks ago that he had been diagnosed with leukemia early in March. "I'm gravely ill and waiting for death," he said. "I pray for it every hour, since leukemia is fatal and my heart is not right."

Jim Lund, planetarium director at El Camino College, where Miller taught for 22 years until retiring in 1974, said he and Miller's wife, Alice, were with him when he died late Tuesday.

"He was lucid until the very, very end, but he was so thin, had lost over 50 pounds and could not eat," said Lund, whose 30-year friendship with Miller began when he was one of Miller's students.

"He did what he wanted to do and he enjoyed it," said Sam Schauerman, an El Camino vice president who was Miller's dean when he was at the college. "Just the fact that he was 'Professor Wonderful' was indicative."

Miller used showmanship to hook people on the basic principles of a field that can be frightening to the uninitiated: physics.

"Demonstrations in physics, that's been my business for 50 years," he recently observed.

In the classroom, Miller used to shout, leap and wave his arms, and he frequently used a phrase from a Greek or Roman philosopher to make a point. But with his favorite audiences--children he visited in their classrooms or spoke to through TV--he used toys, among them a wheel spun on a frame that stores its own energy so it can continue to spin: kinetic energy in action.

"Kids are my favorites," he once said. "Their spirit and curiosity has not yet been dulled by schools."

Miller also found physics at work in the kitchen, showing how housewives could peel onions without tears or bake potatoes faster by using physics-based tricks.

Dressed in a dark coat and open-collared white shirt, Miller made 40 appearances on Walt Disney's "Mickey Mouse Club" and also did a children's record series for Disney on history's great scientists. He also appeared on television with such late-night stars as Steve Allen and Johnny Carson, wrote eight books and published more than 300 papers in professional journals.

Active around the world even after his official retirement at age 65, Miller gave thousands of lectures inside and outside the classroom and made hundreds of television appearances. He had some of his greatest successes in Australia, which he visited more than 20 times, lecturing to large audiences, doing television and even posing for splashy Cadbury chocolate ads.

"I've had my go at it," he said.

Born in Billerica, Mass., Miller grew up in a hard-working farming family and once said he learned the rigors of precise, disciplined thinking from his teachers and his mother, whom he described as "a Lithuanian peasant who spoke 12 languages." By the time he was 16, Miller said, he had "read the (town) library dry."

Worked as a Butler

He left Boston University with degrees in philosophy and theoretical physics. It was the Depression and, failing to land a teaching job, he and the woman who was to become his wife of 52 years became butler and maid for a wealthy Boston doctor, earning $30 a month. He wrote 700 letters before he landed his first teaching job, at a private school in Connecticut.

Miller was a U.S. Army Signal Corps civilian physicist during World War II, held fellowships in physics at the universities of Idaho and Oklahoma and was a Ford Foundation Fellow at UCLA.

The most important intellectual association of his life was formed in 1950, when he went to the Institute for Advanced Studies in Princeton, N.J., and became a student and friend of Albert Einstein, his idol. Miller amassed a collection of Einstein memorabilia that included a copy of Einstein's birth certificate.

Miller taught for a time at UCLA but opted for the then small junior college that was El Camino in 1952 because he did not want to be in a big, remote institution.

Colleagues recall that Miller could be a terror in the classroom, intolerant of misspelled words or misplaced punctuation. Miller also sometimes angered his colleagues because he charged that most faculty were not rigid enough and that students were not learning enough. More than a decade ago, he told another interviewer that intellectual life in America was in trouble, and he never changed his mind.

'Darkness in the Land'

"We are approaching a darkness in the land. Boys and girls are emerging from every level of school with certificates and degrees, but they can't read, write or calculate. We don't have academic honesty or intellectual rigor. Schools have abandoned integrity and rigor."